As the most important electronic element in the field of display technology, TFT is used to control and drive a subpixel of a liquid crystal display (LCD) and an organic light-emitting diode (OLED) display.
Along with the rapid development of the display technology, amorphous silicon (a-Si) TFTs have been gradually replaced with lower temperature poly-silicon (LTPS) TFTs, metal-induced lateral crystallization (MILC) TFTs and oxide TFTs.
For the commonly-used oxide TFT, an oxide semiconductor is used as an active layer, so it has such advantages as large mobility rate, high on-state current, excellent switching characteristic and excellent uniformity. The oxide TFT may be applied to a display device where rapid response and large current are required, e.g., a high-frequency, high-resolution and large-scale display device or an organic light-emitting display device.
However, in the related art, most of the oxide semiconductors contain some rare metal elements, e.g., indium and strontium. An abundance of indium in the earth's crust is merely about 0.049 ppm. Due to the excessive consumption of indium, elemental indium becomes less and less, so its price becomes higher and higher. As a result, the production cost of the display device will increase, and the mass production thereof will be limited.